The art is good, but you need to work on Sakura's child face. It doesn't look very alike. She have a more round face. Her face is way too long and elongated than what it actually is in my opinion. Look here: https://vignette.wikia.nocookie.net/naruto/images/b/bd/Sakura_child.PNG/revision/latest?cb=20140620090026.
Rin, on the other hand, looks very good. Just like what it should be. You have really mastered drawing her, but as said above you can still improve on child Sakura. :)